Flutter i18n version bump, add missing i18n to modules

Bumping flutter_i18n to v0.19.1 as this version seems to work seemlessly again

• Tested on Android (Emulator and physical device, debug and release mode)
• Tested on iOS (Emulator only, debug only)
• Added new key THROW_TRANSLATION_EXCEPTIONS to .env, if set to true this enables TranslationExceptions to be thrown outside of debug mode
• Throw exceptions on missing i18n keys regardless of debug mode (If there's a key missing, I wanna know.)
• fixed some translation issues